United States Patent (19)
`Yamazaki et al.
`
`54 EVAPORATIVE FUEL PROCESSING DEVICE
`75 Inventors: Kazumi Yamazaki; Koichi Hidano;
`Teruo Wakashiro; Takeshi Hara, all
`of Wako; Tomoyuki Kawakami, Haga,
`all of Japan
`73) Assignee: Honda Giken Kogyo Kabushiki
`Kaisha, Tokyo, Japan
`
`(21) Appl. No.: 317,804
`22 Filed:
`Oct. 4, 1994
`30
`Foreign Application Priority Data
`Oct. 4, 1993
`JP
`Japan .................................... 5-248245
`(51) Int. Cl. ................................. F02M 33/02
`52 U.S. Cl. .........
`... 123/520; 123/519
`58 Field of Search ..................................... 123/520,521,
`123/518, 519, 516, 198 D; 55/387
`References Cited
`U.S. PATENT DOCUMENTS
`4,790,283 12/1988 Uranishi .................................. 123/520
`4,815,436 3/1989 Sasaki .......
`123/520
`4,887,578 12/1989 Woodcock
`123/519
`4,951,643 8/1990 Sato ..........
`123/520
`5,056,494 10/1991 Kayanuma .............................. 123/516
`5,337,721
`8/1994 Kasuya .................................... 123/519
`
`56)
`
`
`
`III IIII
`US005456237A
`11
`Patent Number:
`5,456,237
`(45) Date of Patent:
`Oct. 10, 1995
`
`5,393,329 2/1995 Inagaki ou e o so as a w w
`
`a
`
`so a a as a ww. 1231519 R
`
`FOREIGN PATENT DOCUMENTS
`... 123/519
`4121451 4/1992 Japan ......
`123/519
`4153556 5/1992 Japan ......
`... 123/519
`5195884 8/1993 Japan ......
`5280435 10/1993 Japan ..................................... 123/519
`Primary Examiner-Carl S. Miller
`Attorney, Agent, or Firm-Nikaido, Marmelstein, Murray &
`Oram
`ABSTRACT
`57)
`In an evaporative fuel processing device, a canister is
`divided into first, second, third and fourth chambers by
`partition walls. A control valve is provided in a communi
`cation passage which connects the second and third cham
`bers to each other. A first charge passage is connected to an
`upper space in a fuel tank and to a port in the third chamber,
`and a second charge passage is connected to a fuel supply
`valve for the fuel tank and to a port in the first chamber.
`Further, a purge passage is connected to an intake passage of
`an internal combustion engine and to a port in the first
`chamber. The control valve is connected to an electronic
`control unit, and opened during refueling and during trav
`eling of a vehicle and closed during parking of the vehicle.
`Thus, it is possible to reliably prevent an evaporative fuel
`from being released to the atmosphere, while the capacity of
`the canister to a minimum.
`
`5 Claims, 7 Drawing Sheets
`
`BASF-1021
`U.S. Patent No. RE38,844
`
`

`

`US. Patent
`U.S. Patent
`
`Oct. 10, 1995
`Oct. 10, 1995
`
`Sheet 1 of 7
`Sheet 1 of 7
`
`5,456,237
`5,456,237
`
`
`
`
`
`

`

`U.S. Patent
`US. Patent
`
`Oct. 10, 1995
`Oct. 10, 1995
`
`Sheet 2 of 7
`Sheet 2 of 7
`
`5,456,237
`5,456,237
`
`FIG.2A
`FIG.2A
`
`Swami/”MC
`Jr/Az/I/c
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`

`

`U.S. Patent
`US. Patent
`
`
`
`Oct. 10, 1995
`Oct. 10, 1995
`
`Sheet 3 of 7
`Sheet 3 of 7
`
`5,456,237
`5,456,237
`
`
`
`

`

`U.S. Patent
`
`Oct. 10, 1995
`
`Sheet 4 of 7
`
`5,456,237
`
`
`
`FG4B
`
`
`
`
`
`FIG.4D
`
`
`
`

`

`US. Patent
`U.S. Patent
`
`Oct. 10, 1995
`Oct. 10, 1995
`
`Sheet 5 of 7
`Sheet S of 7
`
`5,456,237
`5,456,237
`
`
`
`t
`
`FIG.5
`
`

`

`US. Patent
`U.S. Patent
`
`Oct. 10, 1995
`Oct. 10, 1995
`
`Sheet 6 of 7
`Sheet 6 of 7
`
`5,456,237
`5,456,237
`
`
`
` :JI
`
`V'-
`wer
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`o
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`O
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`al
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`
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`

`

`1.
`EVAPORATIVE FUEL PROCESSING DEVICE
`
`5,456,237
`
`5
`
`10
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`15
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`20
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`25
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`30
`
`BACKGROUND OF THE INVENTION
`1. Field of the Invention
`The present invention relates to an evaporative fuel pro
`cessing device including a canister for adsorbing an evapo
`rative fuel generated in a fuel tank of a vehicle.
`2. Description of the Prior Art
`FIG. 5 illustrates a prior art evaporative fuel processing
`device, in which a first charge passage 01, a second charge
`passage 02 and a purge passage 03 are connected to one of
`end faces of a canister in which an adsorbent is accommo
`dated. An atmosphere-opened passage 04 is defined in the
`other end face. The first charge passage 01 is connected to
`an upper space in a fuel tank Tthrough a two-way valve 05,
`and the second charge passage 02 is connected to a breather
`tube of the fuel tank T through a fuel supply valve 06.
`Further, the purge passage 03 is connected to an intake
`passage of an internal combustion engine through a purge
`valve 07 which is controlled for opening and closing by an
`electronic control unit U.
`With such a prior art evaporative fuel processing device,
`an evaporative fuel generated during parking or traveling of
`a vehicle is charged to the canister C through the first charge
`passage 01, and an evaporative fuel generated during refu
`eling into the vehicle is charged to the canister C through the
`second charge passage 02. The evaporative fuel charged to
`the canister C is purged into the intake passage 08 through
`the purge passage 03.
`FIG. 6 illustrates another prior art evaporative fuel pro
`cessing device, in which a first canister Ca is interposed
`between a first charge passage 01 and a first purge passage
`03a, and a second canister Cb is interposed between a
`second charge passage 02 and a second purge passage 03b.
`Purge valves 07a and 07b are provided in the first and
`second purge passage 03a and 03b, respectively and are
`controlled for opening and closing by an electronic control
`unit U.
`With this evaporative fuel processing device, an evapo
`rative fuel generated during parking and traveling of a
`vehicle is charged to the first canister Ca through the first
`45
`charge passage 01, and an evaporative fuel generated during
`refueling into a vehicle is charged to the second canister Cb
`through the second charge passage 02. The evaporative fuels
`charged to the first and second canisters Ca and Cb are
`purged into the intake passage 08 through the first and
`second purge passages 03a and 03b.
`In the evaporative fuel processing device shown in FIG.
`5, the evaporative fuel generated in the fuel tank T during
`refueling is supplied to the canister C through the second
`charge passage 02 to charge the canister C at a high
`concentration (see FIG. 7A). Thereafter, when the vehicle
`travels, the purge passage 03 is evacuated into a negative
`pressure, causing air to be introduced through the atmo
`sphere-opened passage 04 into the canister C, thereby purg
`ing the canister C. In this case, when the time of traveling of
`the vehicle is long, the purging of the canister is completely
`performed, but when the time of traveling of the vehicle is
`short, only a left half of the canister C near the atmosphere
`opened passage 04 is purged and hence, the concentration of
`fuel adsorbed in the left half is reduced into a lower level,
`but the concentration of fuel adsorbed in the right half is
`maintained at a higher level (see FIG. 7B).
`
`60
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`40
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`50
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`55
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`65
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`When the vehicle is parked to discontinue the purging, the
`adsorbed fuel of the higher concentration in the right half of
`the canister C is diffused into the left half, so that the
`concentration of the adsorbed fuel in the entire canister C is
`brought into a medium level (see FIG.7C). Thereafter, when
`the evaporative fuel is supplied through the first charge
`passage 01 to the canister C due to an increase in tempera
`ture in the fuel tank T, there is caused a problem that the
`evaporative fuel supplied cannot completely be adsorbed to
`the canister C which has already been charged at the medium
`concentration, and such evaporative fuel may be released
`through the atmosphere-opened passage 04 to the atmo
`sphere. (see FIG. 7D).
`In the evaporative fuel processing device shown in FIG.
`6, the two first and second canisters Ca and Cb are required,
`resulting not only in a complicated structure, but also in a
`problem that the first canister Ca does not at all contribute
`to the adsorption of the evaporative fuel generated in a large
`amount during refueling. Therefore, it is necessary to insure
`a large capacity for the second canister Cb and thus, the
`entire canister must be enlarged.
`
`SUMMARY OF THE INVENTION
`Accordingly, it is an object of the present invention to
`reliably prevent the evaporative fuel from being released to
`the atmosphere, without an unneeded increase in capacity of
`the canister.
`To achieve the above object, according to a first aspect
`and feature of the present invention, there is provided an
`evaporative fuel processing device comprising a canister, a
`charge passage connected to a fuel tank and to the canister,
`and a purge passage connected to an intake passage of an
`internal combustion engine and to the canister, in which an
`evaporative fuel generated in the fuel tank is supplied to the
`canister through the charge passage and adsorbed to an
`adsorbent accommodated in the canister, and an evaporative
`fuel released from the adsorbent is supplied into the intake
`passage of the internal combustion engine through the purge
`passage, wherein the device further comprises a first and a
`second adsorbent accommodating space defined in the can
`ister, a communication passage for connecting the first and
`second adsorbent accommodating spaces to each other, a
`control valve provided in the communication passage, and a
`control means for causing the first and second adsorbent
`accommodating spaces to be connected to each other by the
`control valve during refueling into the fuel tank.
`With the first feature, it is possible to insure a sufficient
`adsorbent capacity by using both the adsorbent accommo
`dating spaces during refueling when a large amount of
`evaporative fuel is generated, and to prevent the evaporative
`fuel from being released to the atmosphere.
`In addition to the first feature, according to a second
`aspect and feature of the present invention, the charge
`passage comprises a first charge passage through which the
`evaporative fuel generated during a time other than refueling
`is guided to the second adsorbent accommodating space, and
`a second charge passage through which the evaporative fuel
`generated during refueling is guided to the first adsorbent
`accommodating space.
`With the second feature, it is possible to increase the
`adsorption efficiency of the adsorbent accommodated in
`each of the adsorbent accommodating spaces.
`In addition to the first feature, according to a third aspect
`and feature of the present invention, the control means
`causes the first and second adsorbent accommodating spaces
`
`

`

`5,456,237
`
`3
`to be put into communication with each other by the control
`valve during releasing of the evaporative fuel from the
`canister.
`With the third feature, in releasing the evaporative fuel
`from the canister, the first and second adsorbent accommo
`dating spaces are put into communication with each other by
`the control valve and therefore, it is possible to release the
`adsorbed fuels in both the adsorbent accommodating spaces
`together,
`In addition to the first feature, according to a fourth aspect
`and feature of the present invention, the control means
`causes the first and second adsorbent accommodating spaces
`to be put out of communication with each other by the
`control valve during parking of the vehicle.
`With the fourth feature, it is possible to prevent the
`evaporative fuel from being diffused from the first adsorbent
`accommodating space having a higher concentration of
`evaporative fuel adsorbed into the second adsorbent accom
`modating space having a lower concentration of evaporative
`fuel adsorbed, and to prevent the evaporative fuel from
`being released from the second adsorbent accommodating
`space to the atmosphere during traveling of the vehicle.
`In addition to the first feature, according to a fourth aspect
`and feature of the present invention, the adsorbent accom
`modated in the first adsorbent accommodating space has a
`characteristic that is liable to adsorb high boiling point
`components of the fuel, and the adsorbent accommodated in
`the second adsorbent accommodating space has a charac
`teristic that is liable to adsorb lowly-boiling components of
`the fuel.
`With the fifth feature, it is possible to effectively adsorb
`any of the highly- and lowly-boiling components of the fuel.
`The above and other objects, features and advantages of
`the invention will become apparent from the following
`description of preferred embodiments taken in conjunction
`with the accompanying drawings.
`
`10
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`15
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`20
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`30
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`35
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`40
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`45
`
`4
`valve 4 of an internal combustion engine E. An upper space
`in the fuel tankT is connected with a downstream portion of
`a throttle valve 6 provided in an intake passage 5 in the
`internal combustion engine E by a first charge passage 7 and
`a purge passage 8 between which a canister C is interposed.
`An upper end of a filler tube 9 for supplying an oil to the fuel
`tank T is connected with the internal space in the fuel tank
`T through a breather tube 10. The breather tube 10 is
`connected at its upper end to the canister C through a fuel
`supply valve 11 opened for supplying the oil and a second
`charge passage 12. A two-way valve 13 is provided in the
`first charge passage 7, and a purge valve 14 comprising a
`solenoid valve is provided in the purge passage 8.
`The two-way valve 13 is opened when the internal
`pressure in the fuel tank T is increased to exceed the
`atmospheric pressure by a predetermined value and also
`when the internal pressure in the fuel tank T is reduced to
`below the internal pressure in the canister C by another
`predetermined value, thereby put the fuel tank T and the
`canister C into communication with each other. When the
`purge valve 14 is opened, the canister C and the intake
`passage 5 are put into communication with each other, and
`when the purge valve 14 is closed, the communication
`between the canister C and the intake passage 5 is blocked.
`The canister Cincludes a first to fourth chambers C to C.
`each having an adsorbent comprised of activated carbon
`accommodated therein. The first and second chambers C.
`and C are partitioned from each other by a partition wall 15
`opened at its lower end, and the third and fourth chambers
`C and C are partitioned from each other by a partition wall
`16 opened at its lower end. Further, the second and third
`chambers C and C are partitioned from each other by a
`partition wall 17 having no opening. The first and second
`chambers C and C define a first adsorbent accommodating
`space of the present invention, and the third and fourth
`chambers C and C define a second adsorbent accommo
`dating space of the present invention.
`An evaporative fuel generated from the fuel tank during
`refueling contains a large number of high boiling point
`components. An adsorbent suitable for adsorption of such
`high boiling point components is selected as the adsorbent in
`each of the first and second chambers C and C for mainly
`adsorbing such evaporative fuel. In addition, an evaporative
`fuel generated from the fuel tank during traveling or parking
`of a vehicle contains a large number of low boiling point
`components and therefore, an adsorbent suitable for adsorp
`tion of such low boiling point components is selected as the
`adsorbent in each of the third and fourth chambers C and
`C. The amount of evaporative fuel generated during refu
`eling is larger than the amount of evaporative fuel generated
`during traveling or parking of the vehicle and hence, the
`capacity of the adsorbent in each of the first and second
`chambers C and C is set at a value larger than those of the
`adsorbents in the third and fourth chambers C and C.
`Two ports a and b are provided in an upper portion of the
`first chamber C in the canister C. The port a is connected
`to the second charge passage 12, and the port b is connected
`to the purge passage 8. A port c provided in an upper portion
`of the second chamber C in the canister C and a port d
`provided in an upper portion of the third chamber C are
`connected to each other by a communication passage 18. A
`control valve 19 comprised of a solenoid valve is provided
`in the communication passage 18 for opening and closing
`the latter. Further, a porte provided in an upper space of the
`third chamber C is connected to the first charge passage 7,
`and a port f provided in an upper portion of the fourth
`chamber C is opened to the atmosphere.
`
`BRIEF DESCRIPTION OF THE DRAWENGS
`FIG. 1 is an illustration of the entire arrangement of an
`evaporative fuel processing device according to a first
`embodiment of the present invention;
`FIGS. 2A-2E are views for explaining the operation of
`the first embodiment;
`FIG. 3 is an illustration of the entire arrangement of an
`evaporative fuel processing device according to a second
`embodiment of the present invention;
`FIGS. 4A-4B are views for explaining the operation of
`the second embodiment;
`FIG. 5 is an illustration of the entire arrangement of a
`prior art evaporative fuel processing device;
`FIG. 6 is an illustration of the entire arrangement of
`another prior art evaporative fuel processing device;
`FIGS. 7A-7D are views for explaining the operation of
`the prior art device shown in FIG. 5.
`
`50
`
`55
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`The present invention will now be described by way of
`preferred embodiments in connection with the accompany
`ing drawings.
`As shown in FIG. 1 illustrating a first embodiment, a fuel
`pumped from a fuel tank Tthrough a filter 1 and a fuel pump
`2 is supplied through a feed passage 3 to a fuel injection
`
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`

`5,456,237
`
`5
`The control valve 19 provided in the communication
`passage 18 is connected to an electronic control unit U. The
`control valve 19 is opened during traveling of the vehicle
`and during refueling to the fuel tank T and closed during
`parking of the vehicle. The purge valve 14 provided in the
`purge passage 8 is connected to the electronic control unitU,
`and opened during traveling of the vehicle and closed during
`parking of the vehicle.
`The operation of the first embodiment of the present
`invention having the above-described construction will be
`described below.
`During refueling to the fuel tank T, the fuel supply valve
`11 provided at the upper end of the breather tube 10 is
`opened, thereby permitting air containing the evaporative
`fuel in the fuel tank T to be supplied through the second
`charge passage 12 to the portain the first chamber C in the
`canister C. At this time, the control valve 19 is in its opened
`state, and the purge valve 14 is in its closed state. Therefore,
`the evaporative fuel supplied to the port a charges the first,
`second, third and fourth chambers C, C, C, and C.
`sequentially, and only the air from which the evaporative
`fuel has been removed is released through the port f of the
`fourth chamber C to the atmosphere. In this way, all the first
`to fourth chambers C to C contribute to the adsorption of
`25
`a large amount of evaporative fuel generated during refuel
`ing and therefore, it is possible to minimized the capacity of
`the entire canister C.
`If the vehicle travels in a state in which the fuel supply
`valve 11 is closed upon completion of the refueling and the
`30
`first to fourth chambers C to C in the canister C are
`charged, the purge valve is opened according to a command
`from the electronic control unit U. As a result, the port b in
`the first chamber C is evacuated through the purge passage
`8 by a negative pressure within the intake passage 5, so that
`35
`air is introduced through the port f of the fourth chamber C,
`thereby permitting the fourth, third, second and first cham
`bers C, C, C and C to be purged sequentially. If the time
`of traveling of the vehicle is long, then all the first to fourth
`chambers C to C are purged as shown in FIG. 2E. If the
`time of traveling of the vehicle is short, then the fourth and
`third chambers C and C closer to the port fare completely
`purged, but the second and first chambers C and C far from
`the port fare not completely purged, resulting in a state in
`which some of the adsorbed fuel remains therein.
`45
`When the vehicle is parked after traveling of the vehicle
`for only a short time, the control valve 19 is closed by a
`command from the electronic control unit U to block the
`communication between the second and third chambers C.
`and C, and the purge valve 14 is closed by a command from
`the electronic control unit U. In this manner, the first and
`second chambers C, and C2 are put out of communication
`with the third and fourth chambers C and C by closing of
`the control valve 19 upon parking of the vehicle. Therefore,
`the adsorbed fuel remaining in the first and second chambers
`C and C is reliably prevented from being diffused into the
`third and fourth chambers C and C.
`If the temperature in the fuel tank T is risen by the direct
`rays of the sun or the like during parking of the vehicle, the
`evaporative fuel generated in the fuel tank T is supplied
`through the first charge passage 7 to the porte of the third
`chamber C to charge the third and fourth chambers C and
`C. sequentially as shown in FIG. 2D. During this time, the
`third and fourth chambers C and C have been preferen
`tially purged during traveling of the vehicle as described
`above, and moreover, the adsorbed fuel remaining in the first
`and second chambers C and C is prevented from being
`
`50
`
`55
`
`60
`
`65
`
`10
`
`5
`
`20
`
`40
`
`6
`diffused into the third and fourth chambers C and C by
`closing of the control valve 19 during parking of the vehicle.
`Therefore, a sufficient adsorbing power for the evaporative
`fuel is left in the third and fourth chambers C and C,
`thereby reliably avoiding a disadvantage that an amount of
`the evaporative fuel not completely adsorbed is released
`through the port f to the atmosphere.
`A second embodiment of the present invention will now
`be described in connection with FIGS. 3 and 4.
`As shown in FIG. 3, the second embodiment is different
`from the first embodiment in respect of the connection of
`each passage to the canister C, and is substantially the same
`as the first embodiment in respect of other constructions.
`according to the second embodiment, two ports g and h
`are provided in the first chamber C in the canister C. The
`port g is connected to the second charge passage 12, and a
`check valve 20 for permitting the communication from the
`atmosphere to the first chamber C is connected to the port
`h. A port i provided at an upper portion of the second
`chamber C in the canister C and a port j provided at an
`upper portion of the third chamber C. are connected to each
`other by a communication passage 18. A control valve 19
`comprised of a solenoid valve is provided in the communi
`cation passage 18. The solenoid valve 19 permits the port.j
`and a port k (an atmosphere-opened port), or the ports i and
`j to be selectively put into communication with each other.
`Further, three ports m, n and o are provided in the fourth
`chamber C. The port m is connected to the first charge
`passage 7; the portin is connected to the purge passage 8, and
`a check valve 21 is connected to the porto for permitting the
`fourth chamber C into communication with the atmosphere.
`The control valve 19 provided in the communication
`passage 18 is connected to an electronic control unit U. The
`control valve 19 permits the ports i and j to be put into
`communication with each other during traveling of the
`vehicle and during refueling to the fuel tankT and permits
`the ports j and k to be put into communication with each
`other during parking of the vehicle. The purge valve 14
`provided in the purge passage 8 is opened during traveling
`of the vehicle and closed during parking of the vehicle, as in
`the first embodiment.
`An adsorbent suitable for adsorbing high boiling point
`components of the evaporative fuel liable to be generated
`during traveling of the vehicle and during refueling is
`selected as the adsorbent in each of the first and second
`chambers C, and C, as in the first embodiment. In addition,
`an adsorbent suitable for adsorption of the low boiling point
`components of the evaporative fuel generated from the fuel
`tank during traveling or parking of a vehicle is selected as
`the adsorbent in each of the third and fourth chambers C.
`and C.The capacity of the adsorbent in each of the first and
`second chambers C and C is set at value larger than those
`in the first embodiment, so that most of the evaporative fuel
`generated during refueling is adsorbed to the adsorbents in
`the first and second chambers C and C, and when there is
`an amount of the evaporative fuel not completely adsorbed
`to the adsorbents in the first and second chambers C and C,
`such evaporative fuel is adsorbed to the adsorbents in the
`third and fourth chambers C and C.
`The operation of the second embodiment of the present
`invention having the above-described construction will be
`described below.
`During refueling to the fuel tank T, the fuel supply valve
`11 provided at the upper end of the breather tube 10 is
`opened, thereby permitting air containing the evaporative
`fuel in the fuel tank T to be supplied through the second
`
`

`

`20
`
`7
`charge passage 12 to the port g in the first chamber C to
`charge the first and second chambers C and C sequentially,
`as shown in FIG. 4A. At this time, the third and fourth
`chambers C and C are not charged almost at all, because
`the capacity of the adsorbent in each of the first and second
`chambers C and C is set at a sufficiently large value.
`If the vehicle travels after completion of the refueling, the
`purge valve 14 is opened by a command from the electronic
`control unit U. As a results, the port n of the fourth chamber
`C is evacuated through the purge passage 8 by a negative
`pressure in the intake passage 5, so that the air is introduced
`through the porth of the first chamber C, thereby causing
`the first and second chambers C and C to be purged
`sequentially. When the time of traveling of the vehicle is
`long, the first and second chambers C and C are entirely
`purged. When the time of traveling of the vehicle is short,
`the first and second chambers C and C are not completely
`purged, resulting in a state in which some of the adsorbed
`fuel remains therein.
`When the vehicle is parked after a short traveling, the
`control valve 19 is driven by a command from the electronic
`control unit U to block the communication between the
`second and third chambers C and C, and the purge valve
`14 is closed by a command from the electronic control unit
`U. In this manner, the first and second chambers C and C.
`are put out of communication with the third and fourth
`chambers C and C by closing of the control valve 19 upon
`parking of the vehicle. Therefore, the adsorbed fuel remain
`ing in the first and second chambers C and C is reliably
`prevented from being diffused into the third and fourth
`chambers C and C.
`If the temperature in the fuel tankT is risen by the direct
`rays of the sun or the like during parking of the vehicle, the
`evaporative fuel generated in the fuel tank T is supplied
`through the first charge passage 7 to the port m of the fourth
`chamber C to charge the third and fourth chambers C and
`C. sequentially, as shown in FIG. 4D. During this time, the
`third and fourth chambers C and C are kept uncharged
`during refueling as described above, and moreover, the
`adsorbed fuel remaining in the first and second chambers C
`and C is prevented from being diffused into the third and
`fourth chambers C and C during parking of the vehicle.
`Therefore, a sufficient adsorbing power for the evaporative
`fuel is left in the third and fourth chambers C and C,
`45
`thereby reliably avoiding a disadvantage that a large amount
`of the evaporative fuel which could not be adsorbed is
`released through the port k to the atmosphere.
`Although the embodiments of the present invention have
`been described in detail, it will be understood that the
`present invention is not limited to these embodiments and
`various modifications may be made without departing from
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`the spirit and scope of the invention defined in claims.
`What is claimed is:
`1. An evaporative fuel processing device comprising a
`canister, a charge passage connected to a fuel tank and to the
`canister, and a purge passage connected to an intake passage
`of an internal combustion engine and to the canister, in
`which an evaporative fuel generated in the fuel tank is
`supplied to the canister through the charge passage and
`adsorbed to an adsorbent accommodated in the canister, and
`an evaporative fuel released from the adsorbent is supplied
`into the intake passage of the internal combustion engine
`through the purge passage, wherein said device further
`comprises:
`a first and a second adsorbent accommodating space
`defined in said canister;
`a communication passage for connecting said first and
`second adsorbent accommodating spaces to each other;
`a control valve provided in said communication passage;
`and
`a control means for causing said first and second adsor
`bent accommodating spaces to be connected to each
`other by said control valve during refueling into said
`fuel tank.
`2. An evaporative fuel processing device according to
`claim 1, wherein said charge passage comprises a first
`charge passage through which the evaporative fuel gener
`ated during a time other than refueling is guided to said
`second adsorbent accommodating space, and a second
`charge passage through which the evaporative fuel gener
`ated during refueling is guided to said first adsorbent accom
`modating space.
`3. An evaporative fuel processing device according to
`claim 1, wherein said control means causes said first and
`second adsorbent accommodating spaces to be put into
`communication with each other by said control valve during
`releasing of the evaporative fuel from the canister.
`4. An evaporative fuel processing device according to
`claim 1, wherein said control means causes said first and
`second adsorbent accommodating spaces to be put out of
`communication with each other by said control valve during
`parking of the vehicle.
`5. An evaporative fuel processing device according to
`claim , wherein the adsorbent accommodated in the first
`adsorbent accommodating space has a characteristic that is
`liable to adsorb high boiling point components of the fuel,
`and the adsorbent accommodated in the second adsorbent
`accommodating space has a characteristic that is liable to
`adsorb lowly-boiling components of the fuel.
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